Patents by Inventor Takuya Kochi
Takuya Kochi has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9005378Abstract: Disclosed is a spring steel wire rod that comprises C in a range of 0.35 to 0.65% (mass %, the same applies to respective elements described hereinafter), Si in a range of 1.4 to 2.2%, Mn in a range of 0.10 to 1.0%, Cr in a range of 0.1 to 2.0%, P not more than 0.025% (0% excluded), and S not more than 0.025% (0% excluded), balance comprising iron, and unavoidable impurities, wherein an average grain size Dc of a central part of the steel wire rod is not more than 80 ?m while an average grain size Ds of a surface layer part of the steel wire rod is not less than 3.0 ?m.Type: GrantFiled: August 15, 2008Date of Patent: April 14, 2015Assignee: Kobe Steel, Ltd.Inventors: Takuya Kochi, Shogo Murakami, Takeshi Kuroda, Hiromichi Tsuchiya
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Publication number: 20140377123Abstract: The present invention is a weld metal formed by gas shielded arc welding using a flux cored wire, the welded metal having a predetermined chemical composition, residual austenite particles being present in an amount of at least 2500 particles/mm2, and the volume fraction of residual austenite particles being at least 4.0%.Type: ApplicationFiled: February 25, 2013Publication date: December 25, 2014Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd)Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
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Publication number: 20140086786Abstract: The weld metal of the present invention is formed by gas shield arc welding using a flux-cored wire, has a predetermined chemical component composition, and contains 20% or more of Ti. The amount of Ti-containing oxide particles having a circle-equivalent diameter of 0.15-1.0 ?m is at least 5000 per square mm, the amount of V per total mass of weld metal present as a compound within the weld metal is 0.002% or more, and the average circle equivalent diameter of V-containing carbide present in the weld metal is 15 nm or less.Type: ApplicationFiled: April 6, 2012Publication date: March 27, 2014Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
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Publication number: 20130315777Abstract: Disclosed is a weld metal which is formed by gas-shielded arc welding using a flux-cored wire, and which has a specific chemical composition, in which retained austenite particles are present in a number density of 2500 per square millimeter or more and in a total volume fraction of 4.0% or more based on the total volume of entire structures of the weld metal. The weld metal has excellent hydrogen embrittlement resistance and is resistant to cracking at low temperatures even when the weld metal has a high strength.Type: ApplicationFiled: February 1, 2012Publication date: November 28, 2013Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Hidenori Nako, Takuya Kochi, Wataru Urushihara, Munenobu Sato, Yoshihiko Kitagawa
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Patent number: 8470105Abstract: A high carbon steel wire material which is made of high carbon steel as a raw material for wire products such as steel cords, bead wires, PC steel wires and spring steel, allows for these wire products to be manufactured efficiently at a high wire drawing rate and has excellent wire drawability and a manufacturing process thereof. This high carbon steel wire material is made of a steel material having specific contents of C, Si, Mn, P, S, N, Al and O, and the Bcc-Fe crystal grains of its metal structure have an average crystal grain diameter (Dave) of 20 ?m or less and a maximum crystal grain diameter (Dmax) of 120 ?m or less, preferably an area ratio of crystal grains having a diameter of 80 ?m or more of 40% or less, an average sub grain diameter (dave) of 10 ?m or less, a maximum sub grain diameter (dmax) of 50 ?m or less and a (Dave/dave) ratio of the average crystal grain diameter (Dave) to the average sub grain diameter (dave) of 4.5 or less.Type: GrantFiled: May 15, 2009Date of Patent: June 25, 2013Assignee: Kobe Steele, Ltd.Inventors: Takuya Kochi, Shogo Murakami, Hiroshi Yaguchi, Takeshi Kuroda, Hidenori Sakai, Tomotada Maruo, Takaaki Minamida
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Patent number: 8382916Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: GrantFiled: June 7, 2010Date of Patent: February 26, 2013Assignee: Kobe Steel, Ltd.Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Publication number: 20120325364Abstract: Disclosed is a seamless steel pipe for a high-strength hollow spring, which comprises 0.20 to 0.70 mass % of C, 0.5 to 3.0 mass % of Si, 0.1 to 3.0 mass % of Mn, 0.030 mass % or less (including 0%) of P, 0.030 mass % or less (including 0%) of S, 0.02 mass % or less (including 0%) of N, and the remainder made up by Fe and unavoidable impurities, and which is characterized in that carbide has an equivalent circle diameter of 1.00 ?m or less. The seamless steel pipe enables the production of a hollow spring having high strength and excellent durability.Type: ApplicationFiled: March 3, 2011Publication date: December 27, 2012Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel Ltd.)Inventors: Takuya Kochi, Hitoshi Hatano, Kotaro Toyotake
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Patent number: 8216394Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: GrantFiled: August 14, 2006Date of Patent: July 10, 2012Assignee: Kobe Steel, Ltd.Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Patent number: 8038934Abstract: A spring steel having a high strength of 1900 MPa or more and superior in the brittle fracture resistance, as well as a method for manufacturing the same, are provided. The high strength spring steel comprises, as basic components in mass %, C: 0.4-0.6%, Si: 1.4-3.0%, Mn: 0.1-1.0%, Cr: 0.2-2.5%, P: 0.025% or less, S: 0.025% or less, N: 0.006% or less, Al: 0.1% or less, and O: 0.003% or less, the amount of solute C being 0.15% or less, the amount of Cr contained as a Cr-containing precipitate being 0.10% or less, and a TS value represented by the following equation being 24.8% or more, and in point of structure, the pre-austenite grain diameter being 10 ?m or smaller, wherein TS=28.5*[C]+4.9*[Si]+0.5*[Mn]+2.5*[Cr]+1.7*[V]+3.7*[Mo] where [X] stands for mass % of element X.Type: GrantFiled: January 23, 2007Date of Patent: October 18, 2011Assignee: Kobe Steel, Ltd.Inventors: Takuya Kochi, Hiroshi Yaguchi, Wataru Urushihara
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Publication number: 20110091348Abstract: A steel for heat treatment, which exhibits high strength and high toughness even when the heat treatment (such as quenching and tempering) of the steel is conducted under conventional conditions in an after stage. The steel for heat treatment contains C: 0.10 to 0.70 mass %, Mn: 0.1 to 3.0 mass %, Al: 0.005 to 2.0 mass %, P: 0.050 mass % or less, S: 0.50 mass % or less, O: 0.0030 mass or less, N: 0.0200 mass % or less, and one or more selected from the group consisting of Ti: 0.30 mass % or less and Nb: 0.30 mass or less with the balance being Fe and unavoidable impurities, and has a TH value of 1.0 or above as calculated according to the formula: ({Ti}/48+{Nb}/93) 104 and grain diameters of 10 ?m or below. {Ti} and {Nb} refer respectively to the contents of Ti and Nb in precipitates of 5 to 100 nm in size as determined about their respective extraction residues.Type: ApplicationFiled: June 17, 2009Publication date: April 21, 2011Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Hitoshi Hatano, Takuya Kochi
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Publication number: 20100236667Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: ApplicationFiled: June 7, 2010Publication date: September 23, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Publication number: 20100224287Abstract: A spring steel having a high strength of 1900 MPa or more and superior in the brittle fracture resistance, as well as a method for manufacturing the same, are provided. The high strength spring steel comprises, as basic components in mass %, C: 0.4-0.6%, Si: 1.4-3.0%, Mn: 0.1-1.0%, Cr: 0.2-2.5%, P: 0.025% or less, S: 0.025% or less, N: 0.006% or less, Al: 0.1% or less, and O: 0.003% or less, the amount of solute C being 0.15% or less, the amount of Cr contained as a Cr-containing precipitate being 0.10% or less, and a TS value represented by the following equation being 24.8% or more, and in point of structure, the pre-austenite grain diameter being 10 ?m or smaller, wherein TS=28.5*[C]+4.9*[Si]+0.5*[Mn]+2.5*[Cr]+1.7*[V]+3.7*[Mo] where [X] stands for mass % of element X.Type: ApplicationFiled: January 23, 2007Publication date: September 9, 2010Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takuya Kochi, Hiroshi Yaguchi, Wataru Urushihara
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Patent number: 7618498Abstract: A steel for high-strength springs contains, on the mass basis, 0.35% to 0.65% of C, 1.4% to 2.5% of Si, 0.1% to 1.0% of Mn, 2.0% or less (exclusive of 0%) of Cr, 1.0% or less (exclusive of 0%) of Ni, 1.0% or less (exclusive of 0%) of Cu, 0.020% or less (exclusive of 0%) of P, 0.020% or less (exclusive of 0%) of S, 0.006% or less (exclusive of 0%) of N:, and 0.1% or less (exclusive of 0%) of Al, with the remainder being iron and inevitable impurities, in which Wp(Fe) and W(C) satisfy the following condition: Wp(Fe)>5×W(C), wherein Wp(Fe) is the content of Fe (percent by mass) constituting Fe-containing precipitates in the steel; and W(C) is the carbon content (percent by mass) of the steel. The steel is excellent in cold workability and quality stability.Type: GrantFiled: February 7, 2006Date of Patent: November 17, 2009Assignee: (Kobe Steel, Ltd.)Inventors: Takuya Kochi, Hiroshi Yaguchi, Nao Yoshihara
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Publication number: 20090229710Abstract: The present invention aims at providing a method for production of a steel product which surely retains scale during cooling, storage, and transportation and permits scale to scale off easily at the time of mechanical descaling and pickling that precede the secondary fabrication. The steel product is produced by heating and hot rolling a steel billet and spraying the hot-rolled steel product with steam and/or water mist having a particle diameter no larger than 100 ?m, for surface oxidation.Type: ApplicationFiled: August 14, 2006Publication date: September 17, 2009Applicant: Kabushiki Kaisha Kobe Seiko Sho ( Kobe Steel, Ltd.)Inventors: Takeshi Kuroda, Hidenori Sakai, Mikako Takeda, Takuya Kochi, Takashi Onishi, Tomotada Maruo, Takaaki Minamida
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Publication number: 20090223610Abstract: A high carbon steel wire material which is made of high carbon steel as a raw material for wire products such as steel cords, bead wires, PC steel wires and spring steel, allows for these wire products to be manufactured efficiently at a high wire drawing rate and has excellent wire drawability and a manufacturing process thereof. This high carbon steel wire material is made of a steel material having specific contents of C, Si, Mn, P, S, N, Al and O, and the Bcc-Fe crystal grains of its metal structure have an average crystal grain diameter (Dave) of 20 ?m or less and a maximum crystal grain diameter (Dmax) of 120 ?m or less, preferably an area ratio of crystal grains having a diameter of 80 ?m or more of 40% or less, an average sub grain diameter (dave) of 10 ?m or less, a maximum sub grain diameter (dmax) of 50 ?m or less and a (Dave/dave) ratio of the average crystal grain diameter (Dave) to the average sub grain diameter (dave) of 4.5 or less.Type: ApplicationFiled: May 15, 2009Publication date: September 10, 2009Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takuya KOCHI, Shogo MURAKAMI, Hiroshi YAGUCHI, Takeshi KURODA, Hidenori SAKAI, Tomotada MARUO, Takaaki MINAMIDA
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Publication number: 20090065105Abstract: Disclosed is a spring steel wire rod that comprises C in a range of 0.35 to 0.65% (mass %, the same applies to respective elements described hereinafter), Si in a range of 1.4 to 2.2%, Mn in a range of 0.10 to 1.0%, Cr in a range of 0.1 to 2.0%, P not more than 0.025% % excluded), and S not more than 0.025% (0% excluded), balance comprising iron, and unavoidable impurities, wherein an average grain size Dc of a central part of the steel wire rod is not more than 80 ?tm while an average grain size Ds of a surface layer part of the steel wire rod is not less than 3.0 ?m.Type: ApplicationFiled: August 15, 2008Publication date: March 12, 2009Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd)Inventors: Takuya Kochi, Shogo Murakami, Takeshi Kuroda, Hiromichi Tsuchiya
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Publication number: 20090007998Abstract: A hot-rolled wire rod excelling in wire drawability is provided, in which breakage can be suppressed even in heavy work from a large diameter. A hot-rolled wire rod contains C: 0.35 to 0.65% (percent by mass, hereinafter expressed as well), Si: 1.4 to 3.0%, Mn: 0.10 to 1.0%, Cr: 0.1 to 2.0%, P: 0.025% or less (exclusive of 0%), S: 0.025% or less (exclusive of 0%), N: 0.006% or less (exclusive of 0%), Al: 0.1% or less (exclusive of 0%), and O: 0.0030% or less (exclusive of 0%), with the remnant consisting of Fe and inevitable impurities; wherein the content of hydrogen in steel is 2.50 ppm (ppm by mass, hereinafter expressed as well) or less, and hardness (HV) is 460×C00.1 or less (C0 indicates the content of C (percent by mass) in a position of depth of D/4 (D: diameter of the wire rod)).Type: ApplicationFiled: November 7, 2006Publication date: January 8, 2009Applicant: KAB KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)Inventors: Takuya Kochi, Shogo Murakami, Shoji Miyazaki, Ken Ishida, Masao Toyama, Fujio Koizumi
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Publication number: 20080156403Abstract: Disclosed herein is a steel for high-speed cold working which exhibits good cold workability during working and also exhibits high hardness after working. The steel for high-speed cold working contains C: 0.03 to 0.6% (by mass), Si: 0.005 to 0.6%, Mn: 0.05 to 2%, P: no more than 0.05% (excluding 0%), S: no more than 0.05% (excluding 0%), and N: no more than 0.04% (excluding 0%), with the remainder being iron and inevitable impurities and the amount of dissolved nitrogen in the steel being no less than 0.006%.Type: ApplicationFiled: December 5, 2007Publication date: July 3, 2008Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd)Inventors: Tomokazu MASUDA, Takuya Kochi, Shogo Murakami, Hiroshi Yaguchi
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Publication number: 20070277913Abstract: Disclosed are a wire rod and a method therefor. The wire rod is excellent in wire-drawing workability, insusceptible to wire break in spite of an increase in wire-drawing rate, and reduction of area, and capable of extending a die life by suppressing die wear. The wire rod is made of steel containing C: 0.6 to 1.1%, Si: 0.1 to 2.0%, Mn: 0.1 to 1%, P: not more than 0.20%, S: not more than 0.20%, N: not more than 0.006%, Al: not more than 0.03%, and O: not more than 0.003%, the balance including Fe, and unavoidable impurities. Further, the wire rod comprises a pearlite structure wherein an area ratio of a second-phase ferrite is not more than 11.0%, and a pearlite lamellar spacing is not less than 120 ?m.Type: ApplicationFiled: May 29, 2007Publication date: December 6, 2007Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takuya Kochi, Takeshi Kuroda, Hidenori Sakai, Tomotada Maruo, Shogo Murakami, Hiroshi Yaguchi
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Publication number: 20070125456Abstract: Disclosed herein is a high strength spring steel wire with excellent coiling properties and hydrogen embrittlement resistance. The steel wire comprises, by mass, 0.4 to 0.60% of C, 1.7 to 2.5% of Si, 0.1 to 0.4% of Mn, 0.5 to 2.0% of Cr, 0.015% or less of P (exceeding 0%), 0.015% or less of S (exceeding 0%), 0.006% or less of N (exceeding 0%), 0.001 to 0.07% of Al, and the remainder being Fe and unavoidable impurities. The steel wire has a structure wherein prior austenite has an average grain size of 12 ?m or less, and retained austenite exists in an amount of 1.0 to 8.0 vol. % with respect to a whole structure of the steel wire. The retained austenite has an average grain size of 300 nm or less and a maximum grain size of 800 nm or less. The steel has a tensile strength of 1,900 MPa or more.Type: ApplicationFiled: August 7, 2006Publication date: June 7, 2007Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)Inventors: Takuya Kochi, Hiroshi Yaguchi